N-path filters promise to miniaturize RF receivers by replacing various fixed off-chip filters with a single programmable on-chip filter. This research investigates some of the issues of receivers with N-path filters under strong blocker conditions: reciprocal mixing and inherent nonlinearity. First, a technique for reciprocal mixing cancellation is explored and shown to be impossible using only mixers and baseband impedances. Second, the inherent nonlinearity of both bandpass and notch N-path filters are simulated and modelled. To validate this approach, a highly linear receiver is proposed and designed in 40nm CMOS. The receiver has a bandpass common gate architecture, with a notch filter in the feedback path, improving linearity. The filter is isolated using buffers, improving LO leakage. The common gate stage is IM3 compensated to obtain good
linearity (OOB IIP3 >20 dBm). ... Read more

IoT refers to a network of connected devices that exchange data for different applications using different wireless standards such as Cellular, ZigBee, Bluetooth, Mesh Networks, and the widely used WiFi. For IoT applications that do not require high data rates but require long-range data transmission and low power operation, a sub 1GHz WiFi standard - 802.11ah - was introduced. This thesis focuses on implementing a low power receiver design for IoT application. A reconfigurable zero-IF (ZIF)/ low-IF (LIF) architecture is designed to support the 802.11ah specifications. In the implemented SAW-less receiver design, the input RF signal is directly downconverted by mixing operation to baseband frequencies by current-mode passive mixers. The baseband provides the required selectivity and sensitivity of the system. The receiver provides a 24 – 44 dB programmable gain across 1,2,4 MHz bandwidth. It supports an ACR/NACR of 17 dB/32 dB with an overall power consumption of 4 mW at 6 dB NF. The designed receiver is implemented in TSMC 40 nm and is in the fabrication process. ... Read more